Dent remover with flexible shaft and vibrating means



L. C. FORREST DENT REMOVER WITH FLEXIBLE SHAFT AND VIBRATING MEANS March 20, 1951 2 Sheets-Sheet 1 Filed Oct. 19, 1946 m/ M I ma f C M d m F m-HIP -H March 20, 1951 C, FOR EST DENT REMOVER WITH FLEXIBLE SHAFT AND VIBRATING MEANS Filed Oct. 19, 1946 2 Sheets-Sheet 2 n /0/70 E//6.' f/res/ FlE- E1 2 INVENTOR.

Patented Mar. 2 0, 1951 UNITED STATES PATENT OFF F 1 CE 2,545,878 DENT lRiEMovER WITH FLEXIBLE SHAFT AND VIBRATING MEANS Izon'dell ll-Forrest, Berkeley, Calif. Application October '19, 1946, Serial No. 704,373

M invention "relates to means for removing irregularities "in tubing and i especially concerned with means "for removing dents or depressions in relatively thin-walled, curved andtapered or curved and uniform tubes especially of the nature encountered in many musical instruments Such as comets andtrombones.

"One of the common diffi'culties in connection with instruments of this type is that in a curved portion of the tubing an indentation or depres-- sion is accidentallylproducedwhich not only mars the appearance of the instrument "but is often detrimental to th'e'tone and performance characsev'eral schemes have been heretofore proposed and employed for'the'purpose of removing such internal dents, among others is 'one involving the forcing 'of a succession of balls of gradually increasing diameter through the partially obstructed -tube portion. This is a tedious and sometimes a diiiicul't'opration.

It is an object of my'inve'ntion to provide an improved means "for removing dent's from tubes particularly curved "tubes, and especially curved tu'beshaving 'a taper.

Another object of the invention is "to "provide a means for facilitating and expediting 'the removal of dents from tub" ar or hollow members.

A further object 'oftheinveritioni's to provide a dent remover which can readily 'be utilized in 'eonnection with tubes or hollow vessels o'f'rather widely varying size without'the'n'ecessity of painstakinglyadjust'in'g the "mechanism.

Other objects together with the foregoing are attained in embodiments of the invention dis- "closed in the accompanyin drawings, in which 1 Figure "1 is for the mos't-part a side elevation of a dent remover constructed in accordance with my invention, a portion ofthe musical instrument being shown in-eross section to disclose the interior.

Figure 2 is a detail of a portion of the dent removing mechanism, a part of the ball being shown in cross section and the scale being enlarged. p h V,

Figure 3 is a view similar to Figure 1 but disclosing a modified form of dent remover in accordance with my invention. v

Figure 4 is a detail similar to Figure 2 of the modifiedform o'ftheinvention. v

Figure 5 is asideelevation of a modified form of fiexible'shaft construction.

Figure 6 'is "a fragmentary view, for T the most part in crossfs'ection, showing a shaft arrange- I'n'e'nt rovided with an additional guide tube.

Figure 7 is a fragmentary views howingfiapor- 3 Glaims. (Cl. 153- -805) 2 tion of a tube in cross section together with a modified form of flexible shaft.

Figure 8 is a side elevation of a modified form of dent remover.

Figure 9 is a detail showing in side elevation at modified form of shaft and ball arrangement.

In its preferred embodiment my dent remover is especially designed for use in-connection with a tube having a curve and includes a ball which is receivable within the tube and is connected to an exterior drivin instrumentality by means of a flexible shaft generally rigid in a longitudinal direction but bendable laterally to engage the tubing wall so that upon op'e'rationof the shaft the ball is forced through the tubing and during its progress displaces the tubing wall material to remove the dent.

} 7 While the dent remover of the invention can be embodied in a number of different forms 'depending especially 'upon the particular type of instrument or vessel with which it is to be utilized, I have successfullyemployed it in the form shown in Figures 1 and 2, for example, wherein it is useful in removing dents from a wind instrument such as a comet 6. The cornetincl'udes a bell portion 1 and a tube 8 having agradually diminishing area or tapered cross section as it recedes from the bell and additionally is provided with a curve 9 between the 'bell and a valve H, for example. There is illustrated an identation 12 which is to beremoved.

The structure of my invention includes a ball I 3 of metal or comparable hard material provided with a radially extending threaded recess M engaged with a threaded stud l6 projecting from the end of a link l1. formed but is otherwise part of a shaft comprised of a plurality of comparable links lll'each fastened to the others by a-pivot pin l9 so that the resulting shaft is substantiauy inflexible longitudinally but is flexible laterally. Thelinks l8 between the successive pivot pins I9 are provided'with a smooth, swelled or arcua'te contour 2| to afford good bearing surfaces adapted slidably to engage the interior of the wall of the tube 8 so that bearingpressures are well distributed over a large area to prevent deformation of the wall even when a considerable force is exerted.

The endmost one of the links is is connected -by apin l9 to an inflexible shaft 22 designed to extend through the horn'tubefi and to be secured at its outer'end by an adjustable pivot fastening -23 to a rocking lever 24. The lever is provided 'with an elongated slot 26 forthis purpose and its rocking motion is established by a pivot con- The link 1-? is-specially ilection 21 to a suitable base 28. The lever 24 is rocked by a pitman 29 at one end secured by an adjustable pivot fastening 3| to an elongated slot 32 in the lever 24 and at its other end connected by a wrist pin 33 to a plate 34 rotated by an electric motor 36 or other suitable source of high speed rotation. Thus, the rotary motion of the pin 33 is translated for the most part into a longitudinal oscillation.

With this arrangement when the motor is energized and the pitman 29 is operated, the shaft made up of'the solid portion 22 and of the links is is longitudinally vibrated or has motion with its components principally along the tube and at a relatively rapid rate so that the ball E3 is longitudinally oscillated. The operator presses the comet toward the motor. The force is transmitted to the ball in any position thereof inasmuch as the links bear against the wall of the tube and are therefore effective motion transmitters. The ball it acts as a hammer beating with small amplitude but with high frequency and considerable force upon the indentation i2. The ball gradually pounds from the inside outwardl until the dent is substantially flush with the remaining and correctly formed adjacent portions of the tube. When the dent is tapped out, the ball and shaft are withdrawn and the motor 36 is stopped. In some severe instances the operation is repeated with successive balls of increasing diameter until the dent is hammered out.

Because of the relatively flexible connection 23, the operator can easily hold the horn or tube in his hand while the hammering operation is going on and by twisting it, advancing it and retracting it can hammer the indentation outwardly from various advantageous positions, producing a satisfactory final appearance.

Although the structure is illustrated in Figure 1 as being in contact with the outer wall of the tube, in some instances the withdrawing action of the flexible shaft is more readily employed and in that instance the links it are in contact with the interior shorter radius surface of the horn. Whether the force exerted is one of compression or one of tension, the hammer ball 23 is repeatedly driven against the deformed material to eradicate the discontinuity in the surface.

A somewhat similar arrangement having somewhat the same mode of operation is disclosed in Figures 3 and 4 and has been successfully employed particularly in tubes having a constant or fixed interior area or cross sectional dimension as distinguished from a tapered tube. In this instance the ball 42 is secured to the end of a flexible shaft 43 extending through the horn tube 44. The shaft is secured within a rotary chuck 46 disposed at the end of the spindle 41 of an electric motor 53 mounted on a suitable base 49. The ball :32 is provided with a helical or peripheral groove i and is designed to be approximately of the interior diameter of the tube 4d and of a greater diameter than the tube portion 52 reduced b the indentation.

In the operation of this structure when the motor 48 is energized, the shaft 43 is rotated and bears against the interior. of the wall of the tube 44 and thus transmits its rotational force to the ball 42. The direction of rotation initially is such that the ball d2, due to the engagement of its helical portion with the tube wall, is advanced through the constricted portion 52 and in passing thcrethrough expands the tube into approximately its original configuration. If the exparlsion is suificient the ball 42 is readily retracted. If retraction is difiicult, the direction of motor rotation is reversed, the shaft 43 is likewise reversed, and it makes contact with the other interior surface of the tube 44. The reverse rotation being imparted to the ball 42, the helix is effective to unscrew the ball from the tight portion of the tube so that the ball is easily withdrawn from the interior.

Under some circumstances it is advisable to provide a flexible shaft capable of transmitting longitudinal motion but restricted in its flexibility, or at least so restricted in one direction of bending. For that reason the terminal ball I3 is, as disclosed in Figure 5 provided with a plurality of assembled links Bl held for relative pivotal rotation by pins 62 and adapted to be joined in the same fashion as before, or in a similar fashion, to the shaft 22. In this instance, the links ii are formed with flat surfaces 63 and. 64 so that when the assembled links are properly positioned the surfaces 83 and 64 come into abutment with respect to each other. When in contact the fiat surfaces preclude motion of the flexible section in one lateral direction although they permit complete lateral motion in the other direction. This is of use in preventing rubbing of the flexible section of the shaft against certain portions of the interior of the tube.

As another means of rendering parts of the flexible shaft inflexible under certain circumstances, I disclose in Figure 6 an arrangement in which the structure is substantially identical with that shown in Figures 1 and 2 but in which prior to theinstallation of the ball 13 at the end of the flexible shaft, a rigid tube ll is slipped over the shaft 22 as well as the various links it. This tube H is considerably shorter than the assembled length of the shaft and fits readily with in the tube 8 of the horn. It is propelled along the shaft until it overlies a suflicient number of the links Hi to render that portion substantially inflexible in either direction without interfering with the flexibility of the remaining links.

As a still further modification in Figure 7 there is illustrated an arrangement in which the shaft 8i instead of being connected to a number of articulated links is terminated by connection with a helical coil 82 having the capability of flexing in all lateral directions and being provided at its extremity with a fitting 83 for engagement with a ball 84 identical with the ball 13, for example. In this structure a whipping motion is sometimes induced in the coil 82 so that a relatively small ball 84 may be utilized. Most often balls of successive diameter are introduced and operated in sequence for finally providing the desired interior diameter.

Sometimes the dent is in a position so that no curve-accommodating flexibility is needed. In that instance, as shown in Figure 9, I provide the ball l3 with a substantially rigid shaft 9| which is however of a springy material so that a little yield or give in a lateral direction is normally possible.

In the Figure 8 disclosure there is provided a rigid connection llll between the rocking lever 2 and a step tapered beating shaft m2 so that lateral as well as longitudinal motion components are available at the vibrating extremity of the shaft to effectuate the restoration to their former shape of the metal tube walls being interiorly hammered.

I claim:

1. A dent remover for use in a curved musical instrument tube comprising a ball receivable within said tube; a laterally flexible, longitudinally rigid shaft connected to said ball and receivable within said tube; and means connected to said shaft for rapidly vibrating said shaft and said ball longitudinally.

2. A dent remover for use in a curved musical instrument tube comprising a ball receivable within said tube; a shaft connected to said ball, said shaft being longitudinally rigid but flexible transversely to bear against said tube; and means connected to said shaft for rapidly vibrating said shaft along the wall of said tube and said ball along said tube.

3. A dent remover for use in a curved musical instrument tube comprising a ball receivable within said tube; a plurality of links joined to each other and to said ball, said links having bearing surfaces adapted slidably to engage the Wall of said tube; and means for moving said ball to and fro within said tube by sliding said links along the wall of said tube.

LONDELL C. FORREST.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 203,193 Rehbein Apr. 30, 1878 389,665 Orford Sept. 18, 1888 454,539 Moore June 23, 1891 938,646 Davis NOV. 2, 1909 1,120,271 Buescher Dec. 8, 1914 1,157,073 Baash Oct. 19, 1915 1,530,381 Leedom May 17, 1925 1,604,045 Hathaway Oct. 19, 1926 1,604,736 De Foreest Oct. 26, 1926 1,623,657 Brown Apr. 5, 1927 1,993,361 Cornell May 5, 1935 1,995,368 Sunnen Mar. 26, 1935 2,085,057 Williams June 29, 1937 2,119,875 Carl June 7, 1938 2,237,538 Zublin Apr. 8, 1941 2,345,443 Aiken Mar. 28, 1944 2,357,011 Lampe Aug. 29, 1944 2,423,458 Martin July 8, 1947 FOREIGN PATENTS Number Country Date 5,019 Great Britain Apr. 23, 1885 8,484 Great Britain Apr. 22, 1896 

